catena-Poly[[(1,10-phenanthroline)cobalt]-μ-2,4′-oxydibenzoato]

In the title compound, [Co(C14H8O5)(C12H8N2)]n, the CoII atom is six-coordinated in a distorted octahedral coordination geometry by four O atoms from two chelating carboxylate groups from different 2,4′-oxydibenzoate anions and by two N atoms from a 1,10-phenanthroline (phen) ligand. The two benzene rings of the 2,4′-oxydibenzoate ligand form a dihedral angle of 77.14 (16)°. Adjacent CoII atoms are bridged by 2,4′-oxydibenzoate anions to form a helical chain that propagates along the b-axis direction. Neighboring chains are further assembled by intermolecular π–π stacking interactions between inversion-related phen ligands [centroid-to-centroid distance = 4.0869 (8) Å] to form a two-dimensional supramolecular architecture.

In the title compound, [Co(C 14 H 8 O 5 )(C 12 H 8 N 2 )] n , the Co II atom is six-coordinated in a distorted octahedral coordination geometry by four O atoms from two chelating carboxylate groups from different 2,4 0 -oxydibenzoate anions and by two N atoms from a 1,10-phenanthroline (phen) ligand. The two benzene rings of the 2,4 0 -oxydibenzoate ligand form a dihedral angle of 77.14 (16) . Adjacent Co II atoms are bridged by 2,4 0oxydibenzoate anions to form a helical chain that propagates along the b-axis direction. Neighboring chains are further assembled by intermolecularstacking interactions between inversion-related phen ligands [centroid-to-centroid distance = 4.0869 (8) Å ] to form a two-dimensional supramolecular architecture.

Comment
The rational design and syntheses of metal-organic frameworks has been of increasing interest in the crystal engineering of coordination polymers owing to their ability to provide diverse assemblies with fascinating topological structures and material properties (Han et al., 2005;Xue et al.,2009). The semi-rigid V-shaped multi-carboxylate ligands with two benzene rings, which contain a central molecular framework that can be bridged by an oxygen atom, have sufficient flexibility that they can freely twist around the oxygen atom, leading to metal complexes with diverse structures in the assembly process Wang et al., 2010).
The asymmetric unit contains one Co II ion, one 1,10-phenanthroline ligand and one 2,4′-oxydibenzoate anion. Each Co II atom has a distorted octahedral geometry and is six-coordinated by four O atoms from two chelating carboxylate groups of non-symmetry related 2,4′-oxydibenzoate ligands and by two N atoms from a 1,10-phenanthroline molecule (Fig. 1).

Refinement
All H atoms were positioned geometrically (C-H = 0.93Å) and allowed to ride on their parent atoms, with U iso (H) values equal to 1.2U eq (C).

Figure 2
The helical chain formed by molecules of the title compound that extends along b-axis.

Figure 3
The 2D supramolecular structure formed through π-π interactions. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.003 Δρ max = 0.29 e Å −3 Δρ min = −0.35 e Å −3 Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.